/src/libwebp/src/enc/quant_enc.c
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1 | | // Copyright 2011 Google Inc. All Rights Reserved. |
2 | | // |
3 | | // Use of this source code is governed by a BSD-style license |
4 | | // that can be found in the COPYING file in the root of the source |
5 | | // tree. An additional intellectual property rights grant can be found |
6 | | // in the file PATENTS. All contributing project authors may |
7 | | // be found in the AUTHORS file in the root of the source tree. |
8 | | // ----------------------------------------------------------------------------- |
9 | | // |
10 | | // Quantization |
11 | | // |
12 | | // Author: Skal (pascal.massimino@gmail.com) |
13 | | |
14 | | #include <assert.h> |
15 | | #include <math.h> |
16 | | #include <stdlib.h> // for abs() |
17 | | #include <string.h> |
18 | | |
19 | | #include "src/dec/common_dec.h" |
20 | | #include "src/dsp/dsp.h" |
21 | | #include "src/dsp/quant.h" |
22 | | #include "src/enc/cost_enc.h" |
23 | | #include "src/enc/vp8i_enc.h" |
24 | | #include "src/webp/types.h" |
25 | | |
26 | 0 | #define DO_TRELLIS_I4 1 |
27 | 0 | #define DO_TRELLIS_I16 1 // not a huge gain, but ok at low bitrate. |
28 | 0 | #define DO_TRELLIS_UV 0 // disable trellis for UV. Risky. Not worth. |
29 | | #define USE_TDISTO 1 |
30 | | |
31 | 0 | #define MID_ALPHA 64 // neutral value for susceptibility |
32 | 0 | #define MIN_ALPHA 30 // lowest usable value for susceptibility |
33 | 0 | #define MAX_ALPHA 100 // higher meaningful value for susceptibility |
34 | | |
35 | 0 | #define SNS_TO_DQ 0.9 // Scaling constant between the sns value and the QP |
36 | | // power-law modulation. Must be strictly less than 1. |
37 | | |
38 | | // number of non-zero coeffs below which we consider the block very flat |
39 | | // (and apply a penalty to complex predictions) |
40 | 0 | #define FLATNESS_LIMIT_I16 0 // I16 mode (special case) |
41 | 0 | #define FLATNESS_LIMIT_I4 3 // I4 mode |
42 | 0 | #define FLATNESS_LIMIT_UV 2 // UV mode |
43 | 0 | #define FLATNESS_PENALTY 140 // roughly ~1bit per block |
44 | | |
45 | 0 | #define MULT_8B(a, b) (((a) * (b) + 128) >> 8) |
46 | | |
47 | 0 | #define RD_DISTO_MULT 256 // distortion multiplier (equivalent of lambda) |
48 | | |
49 | | // #define DEBUG_BLOCK |
50 | | |
51 | | //------------------------------------------------------------------------------ |
52 | | |
53 | | #if defined(DEBUG_BLOCK) |
54 | | |
55 | | #include <stdio.h> |
56 | | #include <stdlib.h> |
57 | | |
58 | | static void PrintBlockInfo(const VP8EncIterator* const it, |
59 | | const VP8ModeScore* const rd) { |
60 | | int i, j; |
61 | | const int is_i16 = (it->mb->type == 1); |
62 | | const uint8_t* const y_in = it->yuv_in + Y_OFF_ENC; |
63 | | const uint8_t* const y_out = it->yuv_out + Y_OFF_ENC; |
64 | | const uint8_t* const uv_in = it->yuv_in + U_OFF_ENC; |
65 | | const uint8_t* const uv_out = it->yuv_out + U_OFF_ENC; |
66 | | printf("SOURCE / OUTPUT / ABS DELTA\n"); |
67 | | for (j = 0; j < 16; ++j) { |
68 | | for (i = 0; i < 16; ++i) printf("%3d ", y_in[i + j * BPS]); |
69 | | printf(" "); |
70 | | for (i = 0; i < 16; ++i) printf("%3d ", y_out[i + j * BPS]); |
71 | | printf(" "); |
72 | | for (i = 0; i < 16; ++i) { |
73 | | printf("%1d ", abs(y_in[i + j * BPS] - y_out[i + j * BPS])); |
74 | | } |
75 | | printf("\n"); |
76 | | } |
77 | | printf("\n"); // newline before the U/V block |
78 | | for (j = 0; j < 8; ++j) { |
79 | | for (i = 0; i < 8; ++i) printf("%3d ", uv_in[i + j * BPS]); |
80 | | printf(" "); |
81 | | for (i = 8; i < 16; ++i) printf("%3d ", uv_in[i + j * BPS]); |
82 | | printf(" "); |
83 | | for (i = 0; i < 8; ++i) printf("%3d ", uv_out[i + j * BPS]); |
84 | | printf(" "); |
85 | | for (i = 8; i < 16; ++i) printf("%3d ", uv_out[i + j * BPS]); |
86 | | printf(" "); |
87 | | for (i = 0; i < 8; ++i) { |
88 | | printf("%1d ", abs(uv_out[i + j * BPS] - uv_in[i + j * BPS])); |
89 | | } |
90 | | printf(" "); |
91 | | for (i = 8; i < 16; ++i) { |
92 | | printf("%1d ", abs(uv_out[i + j * BPS] - uv_in[i + j * BPS])); |
93 | | } |
94 | | printf("\n"); |
95 | | } |
96 | | printf("\nD:%d SD:%d R:%d H:%d nz:0x%x score:%d\n", |
97 | | (int)rd->D, (int)rd->SD, (int)rd->R, (int)rd->H, (int)rd->nz, |
98 | | (int)rd->score); |
99 | | if (is_i16) { |
100 | | printf("Mode: %d\n", rd->mode_i16); |
101 | | printf("y_dc_levels:"); |
102 | | for (i = 0; i < 16; ++i) printf("%3d ", rd->y_dc_levels[i]); |
103 | | printf("\n"); |
104 | | } else { |
105 | | printf("Modes[16]: "); |
106 | | for (i = 0; i < 16; ++i) printf("%d ", rd->modes_i4[i]); |
107 | | printf("\n"); |
108 | | } |
109 | | printf("y_ac_levels:\n"); |
110 | | for (j = 0; j < 16; ++j) { |
111 | | for (i = is_i16 ? 1 : 0; i < 16; ++i) { |
112 | | printf("%4d ", rd->y_ac_levels[j][i]); |
113 | | } |
114 | | printf("\n"); |
115 | | } |
116 | | printf("\n"); |
117 | | printf("uv_levels (mode=%d):\n", rd->mode_uv); |
118 | | for (j = 0; j < 8; ++j) { |
119 | | for (i = 0; i < 16; ++i) { |
120 | | printf("%4d ", rd->uv_levels[j][i]); |
121 | | } |
122 | | printf("\n"); |
123 | | } |
124 | | } |
125 | | |
126 | | #endif // DEBUG_BLOCK |
127 | | |
128 | | //------------------------------------------------------------------------------ |
129 | | |
130 | 0 | static WEBP_INLINE int clip(int v, int m, int M) { |
131 | 0 | return v < m ? m : v > M ? M : v; |
132 | 0 | } |
133 | | |
134 | | static const uint8_t kZigzag[16] = { |
135 | | 0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15 |
136 | | }; |
137 | | |
138 | | static const uint8_t kDcTable[128] = { |
139 | | 4, 5, 6, 7, 8, 9, 10, 10, |
140 | | 11, 12, 13, 14, 15, 16, 17, 17, |
141 | | 18, 19, 20, 20, 21, 21, 22, 22, |
142 | | 23, 23, 24, 25, 25, 26, 27, 28, |
143 | | 29, 30, 31, 32, 33, 34, 35, 36, |
144 | | 37, 37, 38, 39, 40, 41, 42, 43, |
145 | | 44, 45, 46, 46, 47, 48, 49, 50, |
146 | | 51, 52, 53, 54, 55, 56, 57, 58, |
147 | | 59, 60, 61, 62, 63, 64, 65, 66, |
148 | | 67, 68, 69, 70, 71, 72, 73, 74, |
149 | | 75, 76, 76, 77, 78, 79, 80, 81, |
150 | | 82, 83, 84, 85, 86, 87, 88, 89, |
151 | | 91, 93, 95, 96, 98, 100, 101, 102, |
152 | | 104, 106, 108, 110, 112, 114, 116, 118, |
153 | | 122, 124, 126, 128, 130, 132, 134, 136, |
154 | | 138, 140, 143, 145, 148, 151, 154, 157 |
155 | | }; |
156 | | |
157 | | static const uint16_t kAcTable[128] = { |
158 | | 4, 5, 6, 7, 8, 9, 10, 11, |
159 | | 12, 13, 14, 15, 16, 17, 18, 19, |
160 | | 20, 21, 22, 23, 24, 25, 26, 27, |
161 | | 28, 29, 30, 31, 32, 33, 34, 35, |
162 | | 36, 37, 38, 39, 40, 41, 42, 43, |
163 | | 44, 45, 46, 47, 48, 49, 50, 51, |
164 | | 52, 53, 54, 55, 56, 57, 58, 60, |
165 | | 62, 64, 66, 68, 70, 72, 74, 76, |
166 | | 78, 80, 82, 84, 86, 88, 90, 92, |
167 | | 94, 96, 98, 100, 102, 104, 106, 108, |
168 | | 110, 112, 114, 116, 119, 122, 125, 128, |
169 | | 131, 134, 137, 140, 143, 146, 149, 152, |
170 | | 155, 158, 161, 164, 167, 170, 173, 177, |
171 | | 181, 185, 189, 193, 197, 201, 205, 209, |
172 | | 213, 217, 221, 225, 229, 234, 239, 245, |
173 | | 249, 254, 259, 264, 269, 274, 279, 284 |
174 | | }; |
175 | | |
176 | | static const uint16_t kAcTable2[128] = { |
177 | | 8, 8, 9, 10, 12, 13, 15, 17, |
178 | | 18, 20, 21, 23, 24, 26, 27, 29, |
179 | | 31, 32, 34, 35, 37, 38, 40, 41, |
180 | | 43, 44, 46, 48, 49, 51, 52, 54, |
181 | | 55, 57, 58, 60, 62, 63, 65, 66, |
182 | | 68, 69, 71, 72, 74, 75, 77, 79, |
183 | | 80, 82, 83, 85, 86, 88, 89, 93, |
184 | | 96, 99, 102, 105, 108, 111, 114, 117, |
185 | | 120, 124, 127, 130, 133, 136, 139, 142, |
186 | | 145, 148, 151, 155, 158, 161, 164, 167, |
187 | | 170, 173, 176, 179, 184, 189, 193, 198, |
188 | | 203, 207, 212, 217, 221, 226, 230, 235, |
189 | | 240, 244, 249, 254, 258, 263, 268, 274, |
190 | | 280, 286, 292, 299, 305, 311, 317, 323, |
191 | | 330, 336, 342, 348, 354, 362, 370, 379, |
192 | | 385, 393, 401, 409, 416, 424, 432, 440 |
193 | | }; |
194 | | |
195 | | static const uint8_t kBiasMatrices[3][2] = { // [luma-ac,luma-dc,chroma][dc,ac] |
196 | | { 96, 110 }, { 96, 108 }, { 110, 115 } |
197 | | }; |
198 | | |
199 | | // Sharpening by (slightly) raising the hi-frequency coeffs. |
200 | | // Hack-ish but helpful for mid-bitrate range. Use with care. |
201 | 0 | #define SHARPEN_BITS 11 // number of descaling bits for sharpening bias |
202 | | static const uint8_t kFreqSharpening[16] = { |
203 | | 0, 30, 60, 90, |
204 | | 30, 60, 90, 90, |
205 | | 60, 90, 90, 90, |
206 | | 90, 90, 90, 90 |
207 | | }; |
208 | | |
209 | | //------------------------------------------------------------------------------ |
210 | | // Initialize quantization parameters in VP8Matrix |
211 | | |
212 | | // Returns the average quantizer |
213 | 0 | static int ExpandMatrix(VP8Matrix* const m, int type) { |
214 | 0 | int i, sum; |
215 | 0 | for (i = 0; i < 2; ++i) { |
216 | 0 | const int is_ac_coeff = (i > 0); |
217 | 0 | const int bias = kBiasMatrices[type][is_ac_coeff]; |
218 | 0 | m->iq[i] = (1 << QFIX) / m->q[i]; |
219 | 0 | m->bias[i] = BIAS(bias); |
220 | | // zthresh is the exact value such that QUANTDIV(coeff, iQ, B) is: |
221 | | // * zero if coeff <= zthresh |
222 | | // * non-zero if coeff > zthresh |
223 | 0 | m->zthresh[i] = ((1 << QFIX) - 1 - m->bias[i]) / m->iq[i]; |
224 | 0 | } |
225 | 0 | for (i = 2; i < 16; ++i) { |
226 | 0 | m->q[i] = m->q[1]; |
227 | 0 | m->iq[i] = m->iq[1]; |
228 | 0 | m->bias[i] = m->bias[1]; |
229 | 0 | m->zthresh[i] = m->zthresh[1]; |
230 | 0 | } |
231 | 0 | for (sum = 0, i = 0; i < 16; ++i) { |
232 | 0 | if (type == 0) { // we only use sharpening for AC luma coeffs |
233 | 0 | m->sharpen[i] = (kFreqSharpening[i] * m->q[i]) >> SHARPEN_BITS; |
234 | 0 | } else { |
235 | 0 | m->sharpen[i] = 0; |
236 | 0 | } |
237 | 0 | sum += m->q[i]; |
238 | 0 | } |
239 | 0 | return (sum + 8) >> 4; |
240 | 0 | } |
241 | | |
242 | 0 | static void CheckLambdaValue(int* const v) { if (*v < 1) *v = 1; } |
243 | | |
244 | 0 | static void SetupMatrices(VP8Encoder* enc) { |
245 | 0 | int i; |
246 | 0 | const int tlambda_scale = |
247 | 0 | (enc->method >= 4) ? enc->config->sns_strength |
248 | 0 | : 0; |
249 | 0 | const int num_segments = enc->segment_hdr.num_segments; |
250 | 0 | for (i = 0; i < num_segments; ++i) { |
251 | 0 | VP8SegmentInfo* const m = &enc->dqm[i]; |
252 | 0 | const int q = m->quant; |
253 | 0 | int q_i4, q_i16, q_uv; |
254 | 0 | m->y1.q[0] = kDcTable[clip(q + enc->dq_y1_dc, 0, 127)]; |
255 | 0 | m->y1.q[1] = kAcTable[clip(q, 0, 127)]; |
256 | |
|
257 | 0 | m->y2.q[0] = kDcTable[ clip(q + enc->dq_y2_dc, 0, 127)] * 2; |
258 | 0 | m->y2.q[1] = kAcTable2[clip(q + enc->dq_y2_ac, 0, 127)]; |
259 | |
|
260 | 0 | m->uv.q[0] = kDcTable[clip(q + enc->dq_uv_dc, 0, 117)]; |
261 | 0 | m->uv.q[1] = kAcTable[clip(q + enc->dq_uv_ac, 0, 127)]; |
262 | |
|
263 | 0 | q_i4 = ExpandMatrix(&m->y1, 0); |
264 | 0 | q_i16 = ExpandMatrix(&m->y2, 1); |
265 | 0 | q_uv = ExpandMatrix(&m->uv, 2); |
266 | |
|
267 | 0 | m->lambda_i4 = (3 * q_i4 * q_i4) >> 7; |
268 | 0 | m->lambda_i16 = (3 * q_i16 * q_i16); |
269 | 0 | m->lambda_uv = (3 * q_uv * q_uv) >> 6; |
270 | 0 | m->lambda_mode = (1 * q_i4 * q_i4) >> 7; |
271 | 0 | m->lambda_trellis_i4 = (7 * q_i4 * q_i4) >> 3; |
272 | 0 | m->lambda_trellis_i16 = (q_i16 * q_i16) >> 2; |
273 | 0 | m->lambda_trellis_uv = (q_uv * q_uv) << 1; |
274 | 0 | m->tlambda = (tlambda_scale * q_i4) >> 5; |
275 | | |
276 | | // none of these constants should be < 1 |
277 | 0 | CheckLambdaValue(&m->lambda_i4); |
278 | 0 | CheckLambdaValue(&m->lambda_i16); |
279 | 0 | CheckLambdaValue(&m->lambda_uv); |
280 | 0 | CheckLambdaValue(&m->lambda_mode); |
281 | 0 | CheckLambdaValue(&m->lambda_trellis_i4); |
282 | 0 | CheckLambdaValue(&m->lambda_trellis_i16); |
283 | 0 | CheckLambdaValue(&m->lambda_trellis_uv); |
284 | 0 | CheckLambdaValue(&m->tlambda); |
285 | |
|
286 | 0 | m->min_disto = 20 * m->y1.q[0]; // quantization-aware min disto |
287 | 0 | m->max_edge = 0; |
288 | |
|
289 | 0 | m->i4_penalty = 1000 * q_i4 * q_i4; |
290 | 0 | } |
291 | 0 | } |
292 | | |
293 | | //------------------------------------------------------------------------------ |
294 | | // Initialize filtering parameters |
295 | | |
296 | | // Very small filter-strength values have close to no visual effect. So we can |
297 | | // save a little decoding-CPU by turning filtering off for these. |
298 | 0 | #define FSTRENGTH_CUTOFF 2 |
299 | | |
300 | 0 | static void SetupFilterStrength(VP8Encoder* const enc) { |
301 | 0 | int i; |
302 | | // level0 is in [0..500]. Using '-f 50' as filter_strength is mid-filtering. |
303 | 0 | const int level0 = 5 * enc->config->filter_strength; |
304 | 0 | for (i = 0; i < NUM_MB_SEGMENTS; ++i) { |
305 | 0 | VP8SegmentInfo* const m = &enc->dqm[i]; |
306 | | // We focus on the quantization of AC coeffs. |
307 | 0 | const int qstep = kAcTable[clip(m->quant, 0, 127)] >> 2; |
308 | 0 | const int base_strength = |
309 | 0 | VP8FilterStrengthFromDelta(enc->filter_hdr.sharpness, qstep); |
310 | | // Segments with lower complexity ('beta') will be less filtered. |
311 | 0 | const int f = base_strength * level0 / (256 + m->beta); |
312 | 0 | m->fstrength = (f < FSTRENGTH_CUTOFF) ? 0 : (f > 63) ? 63 : f; |
313 | 0 | } |
314 | | // We record the initial strength (mainly for the case of 1-segment only). |
315 | 0 | enc->filter_hdr.level = enc->dqm[0].fstrength; |
316 | 0 | enc->filter_hdr.simple = (enc->config->filter_type == 0); |
317 | 0 | enc->filter_hdr.sharpness = enc->config->filter_sharpness; |
318 | 0 | } |
319 | | |
320 | | //------------------------------------------------------------------------------ |
321 | | |
322 | | // Note: if you change the values below, remember that the max range |
323 | | // allowed by the syntax for DQ_UV is [-16,16]. |
324 | 0 | #define MAX_DQ_UV (6) |
325 | 0 | #define MIN_DQ_UV (-4) |
326 | | |
327 | | // We want to emulate jpeg-like behaviour where the expected "good" quality |
328 | | // is around q=75. Internally, our "good" middle is around c=50. So we |
329 | | // map accordingly using linear piece-wise function |
330 | 0 | static double QualityToCompression(double c) { |
331 | 0 | const double linear_c = (c < 0.75) ? c * (2. / 3.) : 2. * c - 1.; |
332 | | // The file size roughly scales as pow(quantizer, 3.). Actually, the |
333 | | // exponent is somewhere between 2.8 and 3.2, but we're mostly interested |
334 | | // in the mid-quant range. So we scale the compressibility inversely to |
335 | | // this power-law: quant ~= compression ^ 1/3. This law holds well for |
336 | | // low quant. Finer modeling for high-quant would make use of kAcTable[] |
337 | | // more explicitly. |
338 | 0 | const double v = pow(linear_c, 1 / 3.); |
339 | 0 | return v; |
340 | 0 | } |
341 | | |
342 | 0 | static double QualityToJPEGCompression(double c, double alpha) { |
343 | | // We map the complexity 'alpha' and quality setting 'c' to a compression |
344 | | // exponent empirically matched to the compression curve of libjpeg6b. |
345 | | // On average, the WebP output size will be roughly similar to that of a |
346 | | // JPEG file compressed with same quality factor. |
347 | 0 | const double amin = 0.30; |
348 | 0 | const double amax = 0.85; |
349 | 0 | const double exp_min = 0.4; |
350 | 0 | const double exp_max = 0.9; |
351 | 0 | const double slope = (exp_min - exp_max) / (amax - amin); |
352 | | // Linearly interpolate 'expn' from exp_min to exp_max |
353 | | // in the [amin, amax] range. |
354 | 0 | const double expn = (alpha > amax) ? exp_min |
355 | 0 | : (alpha < amin) ? exp_max |
356 | 0 | : exp_max + slope * (alpha - amin); |
357 | 0 | const double v = pow(c, expn); |
358 | 0 | return v; |
359 | 0 | } |
360 | | |
361 | | static int SegmentsAreEquivalent(const VP8SegmentInfo* const S1, |
362 | 0 | const VP8SegmentInfo* const S2) { |
363 | 0 | return (S1->quant == S2->quant) && (S1->fstrength == S2->fstrength); |
364 | 0 | } |
365 | | |
366 | 0 | static void SimplifySegments(VP8Encoder* const enc) { |
367 | 0 | int map[NUM_MB_SEGMENTS] = { 0, 1, 2, 3 }; |
368 | | // 'num_segments' is previously validated and <= NUM_MB_SEGMENTS, but an |
369 | | // explicit check is needed to avoid a spurious warning about 'i' exceeding |
370 | | // array bounds of 'dqm' with some compilers (noticed with gcc-4.9). |
371 | 0 | const int num_segments = (enc->segment_hdr.num_segments < NUM_MB_SEGMENTS) |
372 | 0 | ? enc->segment_hdr.num_segments |
373 | 0 | : NUM_MB_SEGMENTS; |
374 | 0 | int num_final_segments = 1; |
375 | 0 | int s1, s2; |
376 | 0 | for (s1 = 1; s1 < num_segments; ++s1) { // find similar segments |
377 | 0 | const VP8SegmentInfo* const S1 = &enc->dqm[s1]; |
378 | 0 | int found = 0; |
379 | | // check if we already have similar segment |
380 | 0 | for (s2 = 0; s2 < num_final_segments; ++s2) { |
381 | 0 | const VP8SegmentInfo* const S2 = &enc->dqm[s2]; |
382 | 0 | if (SegmentsAreEquivalent(S1, S2)) { |
383 | 0 | found = 1; |
384 | 0 | break; |
385 | 0 | } |
386 | 0 | } |
387 | 0 | map[s1] = s2; |
388 | 0 | if (!found) { |
389 | 0 | if (num_final_segments != s1) { |
390 | 0 | enc->dqm[num_final_segments] = enc->dqm[s1]; |
391 | 0 | } |
392 | 0 | ++num_final_segments; |
393 | 0 | } |
394 | 0 | } |
395 | 0 | if (num_final_segments < num_segments) { // Remap |
396 | 0 | int i = enc->mb_w * enc->mb_h; |
397 | 0 | while (i-- > 0) enc->mb_info[i].segment = map[enc->mb_info[i].segment]; |
398 | 0 | enc->segment_hdr.num_segments = num_final_segments; |
399 | | // Replicate the trailing segment infos (it's mostly cosmetics) |
400 | 0 | for (i = num_final_segments; i < num_segments; ++i) { |
401 | 0 | enc->dqm[i] = enc->dqm[num_final_segments - 1]; |
402 | 0 | } |
403 | 0 | } |
404 | 0 | } |
405 | | |
406 | 0 | void VP8SetSegmentParams(VP8Encoder* const enc, float quality) { |
407 | 0 | int i; |
408 | 0 | int dq_uv_ac, dq_uv_dc; |
409 | 0 | const int num_segments = enc->segment_hdr.num_segments; |
410 | 0 | const double amp = SNS_TO_DQ * enc->config->sns_strength / 100. / 128.; |
411 | 0 | const double Q = quality / 100.; |
412 | 0 | const double c_base = enc->config->emulate_jpeg_size ? |
413 | 0 | QualityToJPEGCompression(Q, enc->alpha / 255.) : |
414 | 0 | QualityToCompression(Q); |
415 | 0 | for (i = 0; i < num_segments; ++i) { |
416 | | // We modulate the base coefficient to accommodate for the quantization |
417 | | // susceptibility and allow denser segments to be quantized more. |
418 | 0 | const double expn = 1. - amp * enc->dqm[i].alpha; |
419 | 0 | const double c = pow(c_base, expn); |
420 | 0 | const int q = (int)(127. * (1. - c)); |
421 | 0 | assert(expn > 0.); |
422 | 0 | enc->dqm[i].quant = clip(q, 0, 127); |
423 | 0 | } |
424 | | |
425 | | // purely indicative in the bitstream (except for the 1-segment case) |
426 | 0 | enc->base_quant = enc->dqm[0].quant; |
427 | | |
428 | | // fill-in values for the unused segments (required by the syntax) |
429 | 0 | for (i = num_segments; i < NUM_MB_SEGMENTS; ++i) { |
430 | 0 | enc->dqm[i].quant = enc->base_quant; |
431 | 0 | } |
432 | | |
433 | | // uv_alpha is normally spread around ~60. The useful range is |
434 | | // typically ~30 (quite bad) to ~100 (ok to decimate UV more). |
435 | | // We map it to the safe maximal range of MAX/MIN_DQ_UV for dq_uv. |
436 | 0 | dq_uv_ac = (enc->uv_alpha - MID_ALPHA) * (MAX_DQ_UV - MIN_DQ_UV) |
437 | 0 | / (MAX_ALPHA - MIN_ALPHA); |
438 | | // we rescale by the user-defined strength of adaptation |
439 | 0 | dq_uv_ac = dq_uv_ac * enc->config->sns_strength / 100; |
440 | | // and make it safe. |
441 | 0 | dq_uv_ac = clip(dq_uv_ac, MIN_DQ_UV, MAX_DQ_UV); |
442 | | // We also boost the dc-uv-quant a little, based on sns-strength, since |
443 | | // U/V channels are quite more reactive to high quants (flat DC-blocks |
444 | | // tend to appear, and are unpleasant). |
445 | 0 | dq_uv_dc = -4 * enc->config->sns_strength / 100; |
446 | 0 | dq_uv_dc = clip(dq_uv_dc, -15, 15); // 4bit-signed max allowed |
447 | |
|
448 | 0 | enc->dq_y1_dc = 0; // TODO(skal): dq-lum |
449 | 0 | enc->dq_y2_dc = 0; |
450 | 0 | enc->dq_y2_ac = 0; |
451 | 0 | enc->dq_uv_dc = dq_uv_dc; |
452 | 0 | enc->dq_uv_ac = dq_uv_ac; |
453 | |
|
454 | 0 | SetupFilterStrength(enc); // initialize segments' filtering, eventually |
455 | |
|
456 | 0 | if (num_segments > 1) SimplifySegments(enc); |
457 | |
|
458 | 0 | SetupMatrices(enc); // finalize quantization matrices |
459 | 0 | } |
460 | | |
461 | | //------------------------------------------------------------------------------ |
462 | | // Form the predictions in cache |
463 | | |
464 | | // Must be ordered using {DC_PRED, TM_PRED, V_PRED, H_PRED} as index |
465 | | const uint16_t VP8I16ModeOffsets[4] = { I16DC16, I16TM16, I16VE16, I16HE16 }; |
466 | | const uint16_t VP8UVModeOffsets[4] = { C8DC8, C8TM8, C8VE8, C8HE8 }; |
467 | | |
468 | | // Must be indexed using {B_DC_PRED -> B_HU_PRED} as index |
469 | | static const uint16_t VP8I4ModeOffsets[NUM_BMODES] = { |
470 | | I4DC4, I4TM4, I4VE4, I4HE4, I4RD4, I4VR4, I4LD4, I4VL4, I4HD4, I4HU4 |
471 | | }; |
472 | | |
473 | 0 | void VP8MakeLuma16Preds(const VP8EncIterator* const it) { |
474 | 0 | const uint8_t* const left = it->x ? it->y_left : NULL; |
475 | 0 | const uint8_t* const top = it->y ? it->y_top : NULL; |
476 | 0 | VP8EncPredLuma16(it->yuv_p, left, top); |
477 | 0 | } |
478 | | |
479 | 0 | void VP8MakeChroma8Preds(const VP8EncIterator* const it) { |
480 | 0 | const uint8_t* const left = it->x ? it->u_left : NULL; |
481 | 0 | const uint8_t* const top = it->y ? it->uv_top : NULL; |
482 | 0 | VP8EncPredChroma8(it->yuv_p, left, top); |
483 | 0 | } |
484 | | |
485 | | // Form all the ten Intra4x4 predictions in the 'yuv_p' cache |
486 | | // for the 4x4 block it->i4 |
487 | 0 | static void MakeIntra4Preds(const VP8EncIterator* const it) { |
488 | 0 | VP8EncPredLuma4(it->yuv_p, it->i4_top); |
489 | 0 | } |
490 | | |
491 | | //------------------------------------------------------------------------------ |
492 | | // Quantize |
493 | | |
494 | | // Layout: |
495 | | // +----+----+ |
496 | | // |YYYY|UUVV| 0 |
497 | | // |YYYY|UUVV| 4 |
498 | | // |YYYY|....| 8 |
499 | | // |YYYY|....| 12 |
500 | | // +----+----+ |
501 | | |
502 | | const uint16_t VP8Scan[16] = { // Luma |
503 | | 0 + 0 * BPS, 4 + 0 * BPS, 8 + 0 * BPS, 12 + 0 * BPS, |
504 | | 0 + 4 * BPS, 4 + 4 * BPS, 8 + 4 * BPS, 12 + 4 * BPS, |
505 | | 0 + 8 * BPS, 4 + 8 * BPS, 8 + 8 * BPS, 12 + 8 * BPS, |
506 | | 0 + 12 * BPS, 4 + 12 * BPS, 8 + 12 * BPS, 12 + 12 * BPS, |
507 | | }; |
508 | | |
509 | | static const uint16_t VP8ScanUV[4 + 4] = { |
510 | | 0 + 0 * BPS, 4 + 0 * BPS, 0 + 4 * BPS, 4 + 4 * BPS, // U |
511 | | 8 + 0 * BPS, 12 + 0 * BPS, 8 + 4 * BPS, 12 + 4 * BPS // V |
512 | | }; |
513 | | |
514 | | //------------------------------------------------------------------------------ |
515 | | // Distortion measurement |
516 | | |
517 | | static const uint16_t kWeightY[16] = { |
518 | | 38, 32, 20, 9, 32, 28, 17, 7, 20, 17, 10, 4, 9, 7, 4, 2 |
519 | | }; |
520 | | |
521 | | static const uint16_t kWeightTrellis[16] = { |
522 | | #if USE_TDISTO == 0 |
523 | | 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16 |
524 | | #else |
525 | | 30, 27, 19, 11, |
526 | | 27, 24, 17, 10, |
527 | | 19, 17, 12, 8, |
528 | | 11, 10, 8, 6 |
529 | | #endif |
530 | | }; |
531 | | |
532 | | // Init/Copy the common fields in score. |
533 | 0 | static void InitScore(VP8ModeScore* const rd) { |
534 | 0 | rd->D = 0; |
535 | 0 | rd->SD = 0; |
536 | 0 | rd->R = 0; |
537 | 0 | rd->H = 0; |
538 | 0 | rd->nz = 0; |
539 | 0 | rd->score = MAX_COST; |
540 | 0 | } |
541 | | |
542 | | static void CopyScore(VP8ModeScore* WEBP_RESTRICT const dst, |
543 | 0 | const VP8ModeScore* WEBP_RESTRICT const src) { |
544 | 0 | dst->D = src->D; |
545 | 0 | dst->SD = src->SD; |
546 | 0 | dst->R = src->R; |
547 | 0 | dst->H = src->H; |
548 | 0 | dst->nz = src->nz; // note that nz is not accumulated, but just copied. |
549 | 0 | dst->score = src->score; |
550 | 0 | } |
551 | | |
552 | | static void AddScore(VP8ModeScore* WEBP_RESTRICT const dst, |
553 | 0 | const VP8ModeScore* WEBP_RESTRICT const src) { |
554 | 0 | dst->D += src->D; |
555 | 0 | dst->SD += src->SD; |
556 | 0 | dst->R += src->R; |
557 | 0 | dst->H += src->H; |
558 | 0 | dst->nz |= src->nz; // here, new nz bits are accumulated. |
559 | 0 | dst->score += src->score; |
560 | 0 | } |
561 | | |
562 | | //------------------------------------------------------------------------------ |
563 | | // Performs trellis-optimized quantization. |
564 | | |
565 | | // Trellis node |
566 | | typedef struct { |
567 | | int8_t prev; // best previous node |
568 | | int8_t sign; // sign of coeff_i |
569 | | int16_t level; // level |
570 | | } Node; |
571 | | |
572 | | // Score state |
573 | | typedef struct { |
574 | | score_t score; // partial RD score |
575 | | const uint16_t* costs; // shortcut to cost tables |
576 | | } ScoreState; |
577 | | |
578 | | // If a coefficient was quantized to a value Q (using a neutral bias), |
579 | | // we test all alternate possibilities between [Q-MIN_DELTA, Q+MAX_DELTA] |
580 | | // We don't test negative values though. |
581 | 0 | #define MIN_DELTA 0 // how much lower level to try |
582 | 0 | #define MAX_DELTA 1 // how much higher |
583 | | #define NUM_NODES (MIN_DELTA + 1 + MAX_DELTA) |
584 | 0 | #define NODE(n, l) (nodes[(n)][(l) + MIN_DELTA]) |
585 | 0 | #define SCORE_STATE(n, l) (score_states[n][(l) + MIN_DELTA]) |
586 | | |
587 | 0 | static WEBP_INLINE void SetRDScore(int lambda, VP8ModeScore* const rd) { |
588 | 0 | rd->score = (rd->R + rd->H) * lambda + RD_DISTO_MULT * (rd->D + rd->SD); |
589 | 0 | } |
590 | | |
591 | | static WEBP_INLINE score_t RDScoreTrellis(int lambda, score_t rate, |
592 | 0 | score_t distortion) { |
593 | 0 | return rate * lambda + RD_DISTO_MULT * distortion; |
594 | 0 | } |
595 | | |
596 | | // Coefficient type. |
597 | | enum { TYPE_I16_AC = 0, TYPE_I16_DC = 1, TYPE_CHROMA_A = 2, TYPE_I4_AC = 3 }; |
598 | | |
599 | | static int TrellisQuantizeBlock(const VP8Encoder* WEBP_RESTRICT const enc, |
600 | | int16_t in[16], int16_t out[16], |
601 | | int ctx0, int coeff_type, |
602 | | const VP8Matrix* WEBP_RESTRICT const mtx, |
603 | 0 | int lambda) { |
604 | 0 | const ProbaArray* const probas = enc->proba.coeffs[coeff_type]; |
605 | 0 | CostArrayPtr const costs = |
606 | 0 | (CostArrayPtr)enc->proba.remapped_costs[coeff_type]; |
607 | 0 | const int first = (coeff_type == TYPE_I16_AC) ? 1 : 0; |
608 | 0 | Node nodes[16][NUM_NODES]; |
609 | 0 | ScoreState score_states[2][NUM_NODES]; |
610 | 0 | ScoreState* ss_cur = &SCORE_STATE(0, MIN_DELTA); |
611 | 0 | ScoreState* ss_prev = &SCORE_STATE(1, MIN_DELTA); |
612 | 0 | int best_path[3] = {-1, -1, -1}; // store best-last/best-level/best-previous |
613 | 0 | score_t best_score; |
614 | 0 | int n, m, p, last; |
615 | |
|
616 | 0 | { |
617 | 0 | score_t cost; |
618 | 0 | const int thresh = mtx->q[1] * mtx->q[1] / 4; |
619 | 0 | const int last_proba = probas[VP8EncBands[first]][ctx0][0]; |
620 | | |
621 | | // compute the position of the last interesting coefficient |
622 | 0 | last = first - 1; |
623 | 0 | for (n = 15; n >= first; --n) { |
624 | 0 | const int j = kZigzag[n]; |
625 | 0 | const int err = in[j] * in[j]; |
626 | 0 | if (err > thresh) { |
627 | 0 | last = n; |
628 | 0 | break; |
629 | 0 | } |
630 | 0 | } |
631 | | // we don't need to go inspect up to n = 16 coeffs. We can just go up |
632 | | // to last + 1 (inclusive) without losing much. |
633 | 0 | if (last < 15) ++last; |
634 | | |
635 | | // compute 'skip' score. This is the max score one can do. |
636 | 0 | cost = VP8BitCost(0, last_proba); |
637 | 0 | best_score = RDScoreTrellis(lambda, cost, 0); |
638 | | |
639 | | // initialize source node. |
640 | 0 | for (m = -MIN_DELTA; m <= MAX_DELTA; ++m) { |
641 | 0 | const score_t rate = (ctx0 == 0) ? VP8BitCost(1, last_proba) : 0; |
642 | 0 | ss_cur[m].score = RDScoreTrellis(lambda, rate, 0); |
643 | 0 | ss_cur[m].costs = costs[first][ctx0]; |
644 | 0 | } |
645 | 0 | } |
646 | | |
647 | | // traverse trellis. |
648 | 0 | for (n = first; n <= last; ++n) { |
649 | 0 | const int j = kZigzag[n]; |
650 | 0 | const uint32_t Q = mtx->q[j]; |
651 | 0 | const uint32_t iQ = mtx->iq[j]; |
652 | 0 | const uint32_t B = BIAS(0x00); // neutral bias |
653 | | // note: it's important to take sign of the _original_ coeff, |
654 | | // so we don't have to consider level < 0 afterward. |
655 | 0 | const int sign = (in[j] < 0); |
656 | 0 | const uint32_t coeff0 = (sign ? -in[j] : in[j]) + mtx->sharpen[j]; |
657 | 0 | int level0 = QUANTDIV(coeff0, iQ, B); |
658 | 0 | int thresh_level = QUANTDIV(coeff0, iQ, BIAS(0x80)); |
659 | 0 | if (thresh_level > MAX_LEVEL) thresh_level = MAX_LEVEL; |
660 | 0 | if (level0 > MAX_LEVEL) level0 = MAX_LEVEL; |
661 | |
|
662 | 0 | { // Swap current and previous score states |
663 | 0 | ScoreState* const tmp = ss_cur; |
664 | 0 | ss_cur = ss_prev; |
665 | 0 | ss_prev = tmp; |
666 | 0 | } |
667 | | |
668 | | // test all alternate level values around level0. |
669 | 0 | for (m = -MIN_DELTA; m <= MAX_DELTA; ++m) { |
670 | 0 | Node* const cur = &NODE(n, m); |
671 | 0 | const int level = level0 + m; |
672 | 0 | const int ctx = (level > 2) ? 2 : level; |
673 | 0 | const int band = VP8EncBands[n + 1]; |
674 | 0 | score_t base_score; |
675 | 0 | score_t best_cur_score; |
676 | 0 | int best_prev; |
677 | 0 | score_t cost, score; |
678 | |
|
679 | 0 | ss_cur[m].costs = costs[n + 1][ctx]; |
680 | 0 | if (level < 0 || level > thresh_level) { |
681 | 0 | ss_cur[m].score = MAX_COST; |
682 | | // Node is dead. |
683 | 0 | continue; |
684 | 0 | } |
685 | | |
686 | 0 | { |
687 | | // Compute delta_error = how much coding this level will |
688 | | // subtract to max_error as distortion. |
689 | | // Here, distortion = sum of (|coeff_i| - level_i * Q_i)^2 |
690 | 0 | const int new_error = coeff0 - level * Q; |
691 | 0 | const int delta_error = |
692 | 0 | kWeightTrellis[j] * (new_error * new_error - coeff0 * coeff0); |
693 | 0 | base_score = RDScoreTrellis(lambda, 0, delta_error); |
694 | 0 | } |
695 | | |
696 | | // Inspect all possible non-dead predecessors. Retain only the best one. |
697 | | // The base_score is added to all scores so it is only added for the final |
698 | | // value after the loop. |
699 | 0 | cost = VP8LevelCost(ss_prev[-MIN_DELTA].costs, level); |
700 | 0 | best_cur_score = |
701 | 0 | ss_prev[-MIN_DELTA].score + RDScoreTrellis(lambda, cost, 0); |
702 | 0 | best_prev = -MIN_DELTA; |
703 | 0 | for (p = -MIN_DELTA + 1; p <= MAX_DELTA; ++p) { |
704 | | // Dead nodes (with ss_prev[p].score >= MAX_COST) are automatically |
705 | | // eliminated since their score can't be better than the current best. |
706 | 0 | cost = VP8LevelCost(ss_prev[p].costs, level); |
707 | | // Examine node assuming it's a non-terminal one. |
708 | 0 | score = ss_prev[p].score + RDScoreTrellis(lambda, cost, 0); |
709 | 0 | if (score < best_cur_score) { |
710 | 0 | best_cur_score = score; |
711 | 0 | best_prev = p; |
712 | 0 | } |
713 | 0 | } |
714 | 0 | best_cur_score += base_score; |
715 | | // Store best finding in current node. |
716 | 0 | cur->sign = sign; |
717 | 0 | cur->level = level; |
718 | 0 | cur->prev = best_prev; |
719 | 0 | ss_cur[m].score = best_cur_score; |
720 | | |
721 | | // Now, record best terminal node (and thus best entry in the graph). |
722 | 0 | if (level != 0 && best_cur_score < best_score) { |
723 | 0 | const score_t last_pos_cost = |
724 | 0 | (n < 15) ? VP8BitCost(0, probas[band][ctx][0]) : 0; |
725 | 0 | const score_t last_pos_score = RDScoreTrellis(lambda, last_pos_cost, 0); |
726 | 0 | score = best_cur_score + last_pos_score; |
727 | 0 | if (score < best_score) { |
728 | 0 | best_score = score; |
729 | 0 | best_path[0] = n; // best eob position |
730 | 0 | best_path[1] = m; // best node index |
731 | 0 | best_path[2] = best_prev; // best predecessor |
732 | 0 | } |
733 | 0 | } |
734 | 0 | } |
735 | 0 | } |
736 | | |
737 | | // Fresh start |
738 | | // Beware! We must preserve in[0]/out[0] value for TYPE_I16_AC case. |
739 | 0 | if (coeff_type == TYPE_I16_AC) { |
740 | 0 | memset(in + 1, 0, 15 * sizeof(*in)); |
741 | 0 | memset(out + 1, 0, 15 * sizeof(*out)); |
742 | 0 | } else { |
743 | 0 | memset(in, 0, 16 * sizeof(*in)); |
744 | 0 | memset(out, 0, 16 * sizeof(*out)); |
745 | 0 | } |
746 | 0 | if (best_path[0] == -1) { |
747 | 0 | return 0; // skip! |
748 | 0 | } |
749 | | |
750 | 0 | { |
751 | | // Unwind the best path. |
752 | | // Note: best-prev on terminal node is not necessarily equal to the |
753 | | // best_prev for non-terminal. So we patch best_path[2] in. |
754 | 0 | int nz = 0; |
755 | 0 | int best_node = best_path[1]; |
756 | 0 | n = best_path[0]; |
757 | 0 | NODE(n, best_node).prev = best_path[2]; // force best-prev for terminal |
758 | |
|
759 | 0 | for (; n >= first; --n) { |
760 | 0 | const Node* const node = &NODE(n, best_node); |
761 | 0 | const int j = kZigzag[n]; |
762 | 0 | out[n] = node->sign ? -node->level : node->level; |
763 | 0 | nz |= node->level; |
764 | 0 | in[j] = out[n] * mtx->q[j]; |
765 | 0 | best_node = node->prev; |
766 | 0 | } |
767 | 0 | return (nz != 0); |
768 | 0 | } |
769 | 0 | } |
770 | | |
771 | | #undef NODE |
772 | | |
773 | | //------------------------------------------------------------------------------ |
774 | | // Performs: difference, transform, quantize, back-transform, add |
775 | | // all at once. Output is the reconstructed block in *yuv_out, and the |
776 | | // quantized levels in *levels. |
777 | | |
778 | | static int ReconstructIntra16(VP8EncIterator* WEBP_RESTRICT const it, |
779 | | VP8ModeScore* WEBP_RESTRICT const rd, |
780 | | uint8_t* WEBP_RESTRICT const yuv_out, |
781 | 0 | int mode) { |
782 | 0 | const VP8Encoder* const enc = it->enc; |
783 | 0 | const uint8_t* const ref = it->yuv_p + VP8I16ModeOffsets[mode]; |
784 | 0 | const uint8_t* const src = it->yuv_in + Y_OFF_ENC; |
785 | 0 | const VP8SegmentInfo* const dqm = &enc->dqm[it->mb->segment]; |
786 | 0 | int nz = 0; |
787 | 0 | int n; |
788 | 0 | int16_t tmp[16][16], dc_tmp[16]; |
789 | |
|
790 | 0 | for (n = 0; n < 16; n += 2) { |
791 | 0 | VP8FTransform2(src + VP8Scan[n], ref + VP8Scan[n], tmp[n]); |
792 | 0 | } |
793 | 0 | VP8FTransformWHT(tmp[0], dc_tmp); |
794 | 0 | nz |= VP8EncQuantizeBlockWHT(dc_tmp, rd->y_dc_levels, &dqm->y2) << 24; |
795 | |
|
796 | 0 | if (DO_TRELLIS_I16 && it->do_trellis) { |
797 | 0 | int x, y; |
798 | 0 | VP8IteratorNzToBytes(it); |
799 | 0 | for (y = 0, n = 0; y < 4; ++y) { |
800 | 0 | for (x = 0; x < 4; ++x, ++n) { |
801 | 0 | const int ctx = it->top_nz[x] + it->left_nz[y]; |
802 | 0 | const int non_zero = TrellisQuantizeBlock( |
803 | 0 | enc, tmp[n], rd->y_ac_levels[n], ctx, TYPE_I16_AC, &dqm->y1, |
804 | 0 | dqm->lambda_trellis_i16); |
805 | 0 | it->top_nz[x] = it->left_nz[y] = non_zero; |
806 | 0 | rd->y_ac_levels[n][0] = 0; |
807 | 0 | nz |= non_zero << n; |
808 | 0 | } |
809 | 0 | } |
810 | 0 | } else { |
811 | 0 | for (n = 0; n < 16; n += 2) { |
812 | | // Zero-out the first coeff, so that: a) nz is correct below, and |
813 | | // b) finding 'last' non-zero coeffs in SetResidualCoeffs() is simplified. |
814 | 0 | tmp[n][0] = tmp[n + 1][0] = 0; |
815 | 0 | nz |= VP8EncQuantize2Blocks(tmp[n], rd->y_ac_levels[n], &dqm->y1) << n; |
816 | 0 | assert(rd->y_ac_levels[n + 0][0] == 0); |
817 | 0 | assert(rd->y_ac_levels[n + 1][0] == 0); |
818 | 0 | } |
819 | 0 | } |
820 | | |
821 | | // Transform back |
822 | 0 | VP8TransformWHT(dc_tmp, tmp[0]); |
823 | 0 | for (n = 0; n < 16; n += 2) { |
824 | 0 | VP8ITransform(ref + VP8Scan[n], tmp[n], yuv_out + VP8Scan[n], 1); |
825 | 0 | } |
826 | |
|
827 | 0 | return nz; |
828 | 0 | } |
829 | | |
830 | | static int ReconstructIntra4(VP8EncIterator* WEBP_RESTRICT const it, |
831 | | int16_t levels[16], |
832 | | const uint8_t* WEBP_RESTRICT const src, |
833 | | uint8_t* WEBP_RESTRICT const yuv_out, |
834 | 0 | int mode) { |
835 | 0 | const VP8Encoder* const enc = it->enc; |
836 | 0 | const uint8_t* const ref = it->yuv_p + VP8I4ModeOffsets[mode]; |
837 | 0 | const VP8SegmentInfo* const dqm = &enc->dqm[it->mb->segment]; |
838 | 0 | int nz = 0; |
839 | 0 | int16_t tmp[16]; |
840 | |
|
841 | 0 | VP8FTransform(src, ref, tmp); |
842 | 0 | if (DO_TRELLIS_I4 && it->do_trellis) { |
843 | 0 | const int x = it->i4 & 3, y = it->i4 >> 2; |
844 | 0 | const int ctx = it->top_nz[x] + it->left_nz[y]; |
845 | 0 | nz = TrellisQuantizeBlock(enc, tmp, levels, ctx, TYPE_I4_AC, &dqm->y1, |
846 | 0 | dqm->lambda_trellis_i4); |
847 | 0 | } else { |
848 | 0 | nz = VP8EncQuantizeBlock(tmp, levels, &dqm->y1); |
849 | 0 | } |
850 | 0 | VP8ITransform(ref, tmp, yuv_out, 0); |
851 | 0 | return nz; |
852 | 0 | } |
853 | | |
854 | | //------------------------------------------------------------------------------ |
855 | | // DC-error diffusion |
856 | | |
857 | | // Diffusion weights. We under-correct a bit (15/16th of the error is actually |
858 | | // diffused) to avoid 'rainbow' chessboard pattern of blocks at q~=0. |
859 | 0 | #define C1 7 // fraction of error sent to the 4x4 block below |
860 | 0 | #define C2 8 // fraction of error sent to the 4x4 block on the right |
861 | 0 | #define DSHIFT 4 |
862 | 0 | #define DSCALE 1 // storage descaling, needed to make the error fit int8_t |
863 | | |
864 | | // Quantize as usual, but also compute and return the quantization error. |
865 | | // Error is already divided by DSHIFT. |
866 | | static int QuantizeSingle(int16_t* WEBP_RESTRICT const v, |
867 | 0 | const VP8Matrix* WEBP_RESTRICT const mtx) { |
868 | 0 | int V = *v; |
869 | 0 | const int sign = (V < 0); |
870 | 0 | if (sign) V = -V; |
871 | 0 | if (V > (int)mtx->zthresh[0]) { |
872 | 0 | const int qV = QUANTDIV(V, mtx->iq[0], mtx->bias[0]) * mtx->q[0]; |
873 | 0 | const int err = (V - qV); |
874 | 0 | *v = sign ? -qV : qV; |
875 | 0 | return (sign ? -err : err) >> DSCALE; |
876 | 0 | } |
877 | 0 | *v = 0; |
878 | 0 | return (sign ? -V : V) >> DSCALE; |
879 | 0 | } |
880 | | |
881 | | static void CorrectDCValues(const VP8EncIterator* WEBP_RESTRICT const it, |
882 | | const VP8Matrix* WEBP_RESTRICT const mtx, |
883 | | int16_t tmp[][16], |
884 | 0 | VP8ModeScore* WEBP_RESTRICT const rd) { |
885 | | // | top[0] | top[1] |
886 | | // --------+--------+--------- |
887 | | // left[0] | tmp[0] tmp[1] <-> err0 err1 |
888 | | // left[1] | tmp[2] tmp[3] err2 err3 |
889 | | // |
890 | | // Final errors {err1,err2,err3} are preserved and later restored |
891 | | // as top[]/left[] on the next block. |
892 | 0 | int ch; |
893 | 0 | for (ch = 0; ch <= 1; ++ch) { |
894 | 0 | const int8_t* const top = it->top_derr[it->x][ch]; |
895 | 0 | const int8_t* const left = it->left_derr[ch]; |
896 | 0 | int16_t (* const c)[16] = &tmp[ch * 4]; |
897 | 0 | int err0, err1, err2, err3; |
898 | 0 | c[0][0] += (C1 * top[0] + C2 * left[0]) >> (DSHIFT - DSCALE); |
899 | 0 | err0 = QuantizeSingle(&c[0][0], mtx); |
900 | 0 | c[1][0] += (C1 * top[1] + C2 * err0) >> (DSHIFT - DSCALE); |
901 | 0 | err1 = QuantizeSingle(&c[1][0], mtx); |
902 | 0 | c[2][0] += (C1 * err0 + C2 * left[1]) >> (DSHIFT - DSCALE); |
903 | 0 | err2 = QuantizeSingle(&c[2][0], mtx); |
904 | 0 | c[3][0] += (C1 * err1 + C2 * err2) >> (DSHIFT - DSCALE); |
905 | 0 | err3 = QuantizeSingle(&c[3][0], mtx); |
906 | | // error 'err' is bounded by mtx->q[0] which is 132 at max. Hence |
907 | | // err >> DSCALE will fit in an int8_t type if DSCALE>=1. |
908 | 0 | assert(abs(err1) <= 127 && abs(err2) <= 127 && abs(err3) <= 127); |
909 | 0 | rd->derr[ch][0] = (int8_t)err1; |
910 | 0 | rd->derr[ch][1] = (int8_t)err2; |
911 | 0 | rd->derr[ch][2] = (int8_t)err3; |
912 | 0 | } |
913 | 0 | } |
914 | | |
915 | | static void StoreDiffusionErrors(VP8EncIterator* WEBP_RESTRICT const it, |
916 | 0 | const VP8ModeScore* WEBP_RESTRICT const rd) { |
917 | 0 | int ch; |
918 | 0 | for (ch = 0; ch <= 1; ++ch) { |
919 | 0 | int8_t* const top = it->top_derr[it->x][ch]; |
920 | 0 | int8_t* const left = it->left_derr[ch]; |
921 | 0 | left[0] = rd->derr[ch][0]; // restore err1 |
922 | 0 | left[1] = 3 * rd->derr[ch][2] >> 2; // ... 3/4th of err3 |
923 | 0 | top[0] = rd->derr[ch][1]; // ... err2 |
924 | 0 | top[1] = rd->derr[ch][2] - left[1]; // ... 1/4th of err3. |
925 | 0 | } |
926 | 0 | } |
927 | | |
928 | | #undef C1 |
929 | | #undef C2 |
930 | | #undef DSHIFT |
931 | | #undef DSCALE |
932 | | |
933 | | //------------------------------------------------------------------------------ |
934 | | |
935 | | static int ReconstructUV(VP8EncIterator* WEBP_RESTRICT const it, |
936 | | VP8ModeScore* WEBP_RESTRICT const rd, |
937 | 0 | uint8_t* WEBP_RESTRICT const yuv_out, int mode) { |
938 | 0 | const VP8Encoder* const enc = it->enc; |
939 | 0 | const uint8_t* const ref = it->yuv_p + VP8UVModeOffsets[mode]; |
940 | 0 | const uint8_t* const src = it->yuv_in + U_OFF_ENC; |
941 | 0 | const VP8SegmentInfo* const dqm = &enc->dqm[it->mb->segment]; |
942 | 0 | int nz = 0; |
943 | 0 | int n; |
944 | 0 | int16_t tmp[8][16]; |
945 | |
|
946 | 0 | for (n = 0; n < 8; n += 2) { |
947 | 0 | VP8FTransform2(src + VP8ScanUV[n], ref + VP8ScanUV[n], tmp[n]); |
948 | 0 | } |
949 | 0 | if (it->top_derr != NULL) CorrectDCValues(it, &dqm->uv, tmp, rd); |
950 | |
|
951 | 0 | if (DO_TRELLIS_UV && it->do_trellis) { |
952 | 0 | int ch, x, y; |
953 | 0 | for (ch = 0, n = 0; ch <= 2; ch += 2) { |
954 | 0 | for (y = 0; y < 2; ++y) { |
955 | 0 | for (x = 0; x < 2; ++x, ++n) { |
956 | 0 | const int ctx = it->top_nz[4 + ch + x] + it->left_nz[4 + ch + y]; |
957 | 0 | const int non_zero = TrellisQuantizeBlock( |
958 | 0 | enc, tmp[n], rd->uv_levels[n], ctx, TYPE_CHROMA_A, &dqm->uv, |
959 | 0 | dqm->lambda_trellis_uv); |
960 | 0 | it->top_nz[4 + ch + x] = it->left_nz[4 + ch + y] = non_zero; |
961 | 0 | nz |= non_zero << n; |
962 | 0 | } |
963 | 0 | } |
964 | 0 | } |
965 | 0 | } else { |
966 | 0 | for (n = 0; n < 8; n += 2) { |
967 | 0 | nz |= VP8EncQuantize2Blocks(tmp[n], rd->uv_levels[n], &dqm->uv) << n; |
968 | 0 | } |
969 | 0 | } |
970 | |
|
971 | 0 | for (n = 0; n < 8; n += 2) { |
972 | 0 | VP8ITransform(ref + VP8ScanUV[n], tmp[n], yuv_out + VP8ScanUV[n], 1); |
973 | 0 | } |
974 | 0 | return (nz << 16); |
975 | 0 | } |
976 | | |
977 | | //------------------------------------------------------------------------------ |
978 | | // RD-opt decision. Reconstruct each modes, evalue distortion and bit-cost. |
979 | | // Pick the mode is lower RD-cost = Rate + lambda * Distortion. |
980 | | |
981 | 0 | static void StoreMaxDelta(VP8SegmentInfo* const dqm, const int16_t DCs[16]) { |
982 | | // We look at the first three AC coefficients to determine what is the average |
983 | | // delta between each sub-4x4 block. |
984 | 0 | const int v0 = abs(DCs[1]); |
985 | 0 | const int v1 = abs(DCs[2]); |
986 | 0 | const int v2 = abs(DCs[4]); |
987 | 0 | int max_v = (v1 > v0) ? v1 : v0; |
988 | 0 | max_v = (v2 > max_v) ? v2 : max_v; |
989 | 0 | if (max_v > dqm->max_edge) dqm->max_edge = max_v; |
990 | 0 | } |
991 | | |
992 | 0 | static void SwapModeScore(VP8ModeScore** a, VP8ModeScore** b) { |
993 | 0 | VP8ModeScore* const tmp = *a; |
994 | 0 | *a = *b; |
995 | 0 | *b = tmp; |
996 | 0 | } |
997 | | |
998 | 0 | static void SwapPtr(uint8_t** a, uint8_t** b) { |
999 | 0 | uint8_t* const tmp = *a; |
1000 | 0 | *a = *b; |
1001 | 0 | *b = tmp; |
1002 | 0 | } |
1003 | | |
1004 | 0 | static void SwapOut(VP8EncIterator* const it) { |
1005 | 0 | SwapPtr(&it->yuv_out, &it->yuv_out2); |
1006 | 0 | } |
1007 | | |
1008 | | static void PickBestIntra16(VP8EncIterator* WEBP_RESTRICT const it, |
1009 | 0 | VP8ModeScore* WEBP_RESTRICT rd) { |
1010 | 0 | const int kNumBlocks = 16; |
1011 | 0 | VP8SegmentInfo* const dqm = &it->enc->dqm[it->mb->segment]; |
1012 | 0 | const int lambda = dqm->lambda_i16; |
1013 | 0 | const int tlambda = dqm->tlambda; |
1014 | 0 | const uint8_t* const src = it->yuv_in + Y_OFF_ENC; |
1015 | 0 | VP8ModeScore rd_tmp; |
1016 | 0 | VP8ModeScore* rd_cur = &rd_tmp; |
1017 | 0 | VP8ModeScore* rd_best = rd; |
1018 | 0 | int mode; |
1019 | 0 | int is_flat = IsFlatSource16(it->yuv_in + Y_OFF_ENC); |
1020 | |
|
1021 | 0 | rd->mode_i16 = -1; |
1022 | 0 | for (mode = 0; mode < NUM_PRED_MODES; ++mode) { |
1023 | 0 | uint8_t* const tmp_dst = it->yuv_out2 + Y_OFF_ENC; // scratch buffer |
1024 | 0 | rd_cur->mode_i16 = mode; |
1025 | | |
1026 | | // Reconstruct |
1027 | 0 | rd_cur->nz = ReconstructIntra16(it, rd_cur, tmp_dst, mode); |
1028 | | |
1029 | | // Measure RD-score |
1030 | 0 | rd_cur->D = VP8SSE16x16(src, tmp_dst); |
1031 | 0 | rd_cur->SD = |
1032 | 0 | tlambda ? MULT_8B(tlambda, VP8TDisto16x16(src, tmp_dst, kWeightY)) : 0; |
1033 | 0 | rd_cur->H = VP8FixedCostsI16[mode]; |
1034 | 0 | rd_cur->R = VP8GetCostLuma16(it, rd_cur); |
1035 | 0 | if (is_flat) { |
1036 | | // refine the first impression (which was in pixel space) |
1037 | 0 | is_flat = IsFlat(rd_cur->y_ac_levels[0], kNumBlocks, FLATNESS_LIMIT_I16); |
1038 | 0 | if (is_flat) { |
1039 | | // Block is very flat. We put emphasis on the distortion being very low! |
1040 | 0 | rd_cur->D *= 2; |
1041 | 0 | rd_cur->SD *= 2; |
1042 | 0 | } |
1043 | 0 | } |
1044 | | |
1045 | | // Since we always examine Intra16 first, we can overwrite *rd directly. |
1046 | 0 | SetRDScore(lambda, rd_cur); |
1047 | 0 | if (mode == 0 || rd_cur->score < rd_best->score) { |
1048 | 0 | SwapModeScore(&rd_cur, &rd_best); |
1049 | 0 | SwapOut(it); |
1050 | 0 | } |
1051 | 0 | } |
1052 | 0 | if (rd_best != rd) { |
1053 | 0 | memcpy(rd, rd_best, sizeof(*rd)); |
1054 | 0 | } |
1055 | 0 | SetRDScore(dqm->lambda_mode, rd); // finalize score for mode decision. |
1056 | 0 | VP8SetIntra16Mode(it, rd->mode_i16); |
1057 | | |
1058 | | // we have a blocky macroblock (only DCs are non-zero) with fairly high |
1059 | | // distortion, record max delta so we can later adjust the minimal filtering |
1060 | | // strength needed to smooth these blocks out. |
1061 | 0 | if ((rd->nz & 0x100ffff) == 0x1000000 && rd->D > dqm->min_disto) { |
1062 | 0 | StoreMaxDelta(dqm, rd->y_dc_levels); |
1063 | 0 | } |
1064 | 0 | } |
1065 | | |
1066 | | //------------------------------------------------------------------------------ |
1067 | | |
1068 | | // return the cost array corresponding to the surrounding prediction modes. |
1069 | | static const uint16_t* GetCostModeI4(VP8EncIterator* WEBP_RESTRICT const it, |
1070 | 0 | const uint8_t modes[16]) { |
1071 | 0 | const int preds_w = it->enc->preds_w; |
1072 | 0 | const int x = (it->i4 & 3), y = it->i4 >> 2; |
1073 | 0 | const int left = (x == 0) ? it->preds[y * preds_w - 1] : modes[it->i4 - 1]; |
1074 | 0 | const int top = (y == 0) ? it->preds[-preds_w + x] : modes[it->i4 - 4]; |
1075 | 0 | return VP8FixedCostsI4[top][left]; |
1076 | 0 | } |
1077 | | |
1078 | | static int PickBestIntra4(VP8EncIterator* WEBP_RESTRICT const it, |
1079 | 0 | VP8ModeScore* WEBP_RESTRICT const rd) { |
1080 | 0 | const VP8Encoder* const enc = it->enc; |
1081 | 0 | const VP8SegmentInfo* const dqm = &enc->dqm[it->mb->segment]; |
1082 | 0 | const int lambda = dqm->lambda_i4; |
1083 | 0 | const int tlambda = dqm->tlambda; |
1084 | 0 | const uint8_t* const src0 = it->yuv_in + Y_OFF_ENC; |
1085 | 0 | uint8_t* const best_blocks = it->yuv_out2 + Y_OFF_ENC; |
1086 | 0 | int total_header_bits = 0; |
1087 | 0 | VP8ModeScore rd_best; |
1088 | |
|
1089 | 0 | if (enc->max_i4_header_bits == 0) { |
1090 | 0 | return 0; |
1091 | 0 | } |
1092 | | |
1093 | 0 | InitScore(&rd_best); |
1094 | 0 | rd_best.H = 211; // '211' is the value of VP8BitCost(0, 145) |
1095 | 0 | SetRDScore(dqm->lambda_mode, &rd_best); |
1096 | 0 | VP8IteratorStartI4(it); |
1097 | 0 | do { |
1098 | 0 | const int kNumBlocks = 1; |
1099 | 0 | VP8ModeScore rd_i4; |
1100 | 0 | int mode; |
1101 | 0 | int best_mode = -1; |
1102 | 0 | const uint8_t* const src = src0 + VP8Scan[it->i4]; |
1103 | 0 | const uint16_t* const mode_costs = GetCostModeI4(it, rd->modes_i4); |
1104 | 0 | uint8_t* best_block = best_blocks + VP8Scan[it->i4]; |
1105 | 0 | uint8_t* tmp_dst = it->yuv_p + I4TMP; // scratch buffer. |
1106 | |
|
1107 | 0 | InitScore(&rd_i4); |
1108 | 0 | MakeIntra4Preds(it); |
1109 | 0 | for (mode = 0; mode < NUM_BMODES; ++mode) { |
1110 | 0 | VP8ModeScore rd_tmp; |
1111 | 0 | int16_t tmp_levels[16]; |
1112 | | |
1113 | | // Reconstruct |
1114 | 0 | rd_tmp.nz = |
1115 | 0 | ReconstructIntra4(it, tmp_levels, src, tmp_dst, mode) << it->i4; |
1116 | | |
1117 | | // Compute RD-score |
1118 | 0 | rd_tmp.D = VP8SSE4x4(src, tmp_dst); |
1119 | 0 | rd_tmp.SD = |
1120 | 0 | tlambda ? MULT_8B(tlambda, VP8TDisto4x4(src, tmp_dst, kWeightY)) |
1121 | 0 | : 0; |
1122 | 0 | rd_tmp.H = mode_costs[mode]; |
1123 | | |
1124 | | // Add flatness penalty, to avoid flat area to be mispredicted |
1125 | | // by a complex mode. |
1126 | 0 | if (mode > 0 && IsFlat(tmp_levels, kNumBlocks, FLATNESS_LIMIT_I4)) { |
1127 | 0 | rd_tmp.R = FLATNESS_PENALTY * kNumBlocks; |
1128 | 0 | } else { |
1129 | 0 | rd_tmp.R = 0; |
1130 | 0 | } |
1131 | | |
1132 | | // early-out check |
1133 | 0 | SetRDScore(lambda, &rd_tmp); |
1134 | 0 | if (best_mode >= 0 && rd_tmp.score >= rd_i4.score) continue; |
1135 | | |
1136 | | // finish computing score |
1137 | 0 | rd_tmp.R += VP8GetCostLuma4(it, tmp_levels); |
1138 | 0 | SetRDScore(lambda, &rd_tmp); |
1139 | |
|
1140 | 0 | if (best_mode < 0 || rd_tmp.score < rd_i4.score) { |
1141 | 0 | CopyScore(&rd_i4, &rd_tmp); |
1142 | 0 | best_mode = mode; |
1143 | 0 | SwapPtr(&tmp_dst, &best_block); |
1144 | 0 | memcpy(rd_best.y_ac_levels[it->i4], tmp_levels, |
1145 | 0 | sizeof(rd_best.y_ac_levels[it->i4])); |
1146 | 0 | } |
1147 | 0 | } |
1148 | 0 | SetRDScore(dqm->lambda_mode, &rd_i4); |
1149 | 0 | AddScore(&rd_best, &rd_i4); |
1150 | 0 | if (rd_best.score >= rd->score) { |
1151 | 0 | return 0; |
1152 | 0 | } |
1153 | 0 | total_header_bits += (int)rd_i4.H; // <- equal to mode_costs[best_mode]; |
1154 | 0 | if (total_header_bits > enc->max_i4_header_bits) { |
1155 | 0 | return 0; |
1156 | 0 | } |
1157 | | // Copy selected samples if not in the right place already. |
1158 | 0 | if (best_block != best_blocks + VP8Scan[it->i4]) { |
1159 | 0 | VP8Copy4x4(best_block, best_blocks + VP8Scan[it->i4]); |
1160 | 0 | } |
1161 | 0 | rd->modes_i4[it->i4] = best_mode; |
1162 | 0 | it->top_nz[it->i4 & 3] = it->left_nz[it->i4 >> 2] = (rd_i4.nz ? 1 : 0); |
1163 | 0 | } while (VP8IteratorRotateI4(it, best_blocks)); |
1164 | | |
1165 | | // finalize state |
1166 | 0 | CopyScore(rd, &rd_best); |
1167 | 0 | VP8SetIntra4Mode(it, rd->modes_i4); |
1168 | 0 | SwapOut(it); |
1169 | 0 | memcpy(rd->y_ac_levels, rd_best.y_ac_levels, sizeof(rd->y_ac_levels)); |
1170 | 0 | return 1; // select intra4x4 over intra16x16 |
1171 | 0 | } |
1172 | | |
1173 | | //------------------------------------------------------------------------------ |
1174 | | |
1175 | | static void PickBestUV(VP8EncIterator* WEBP_RESTRICT const it, |
1176 | 0 | VP8ModeScore* WEBP_RESTRICT const rd) { |
1177 | 0 | const int kNumBlocks = 8; |
1178 | 0 | const VP8SegmentInfo* const dqm = &it->enc->dqm[it->mb->segment]; |
1179 | 0 | const int lambda = dqm->lambda_uv; |
1180 | 0 | const uint8_t* const src = it->yuv_in + U_OFF_ENC; |
1181 | 0 | uint8_t* tmp_dst = it->yuv_out2 + U_OFF_ENC; // scratch buffer |
1182 | 0 | uint8_t* dst0 = it->yuv_out + U_OFF_ENC; |
1183 | 0 | uint8_t* dst = dst0; |
1184 | 0 | VP8ModeScore rd_best; |
1185 | 0 | int mode; |
1186 | |
|
1187 | 0 | rd->mode_uv = -1; |
1188 | 0 | InitScore(&rd_best); |
1189 | 0 | for (mode = 0; mode < NUM_PRED_MODES; ++mode) { |
1190 | 0 | VP8ModeScore rd_uv; |
1191 | | |
1192 | | // Reconstruct |
1193 | 0 | rd_uv.nz = ReconstructUV(it, &rd_uv, tmp_dst, mode); |
1194 | | |
1195 | | // Compute RD-score |
1196 | 0 | rd_uv.D = VP8SSE16x8(src, tmp_dst); |
1197 | 0 | rd_uv.SD = 0; // not calling TDisto here: it tends to flatten areas. |
1198 | 0 | rd_uv.H = VP8FixedCostsUV[mode]; |
1199 | 0 | rd_uv.R = VP8GetCostUV(it, &rd_uv); |
1200 | 0 | if (mode > 0 && IsFlat(rd_uv.uv_levels[0], kNumBlocks, FLATNESS_LIMIT_UV)) { |
1201 | 0 | rd_uv.R += FLATNESS_PENALTY * kNumBlocks; |
1202 | 0 | } |
1203 | |
|
1204 | 0 | SetRDScore(lambda, &rd_uv); |
1205 | 0 | if (mode == 0 || rd_uv.score < rd_best.score) { |
1206 | 0 | CopyScore(&rd_best, &rd_uv); |
1207 | 0 | rd->mode_uv = mode; |
1208 | 0 | memcpy(rd->uv_levels, rd_uv.uv_levels, sizeof(rd->uv_levels)); |
1209 | 0 | if (it->top_derr != NULL) { |
1210 | 0 | memcpy(rd->derr, rd_uv.derr, sizeof(rd_uv.derr)); |
1211 | 0 | } |
1212 | 0 | SwapPtr(&dst, &tmp_dst); |
1213 | 0 | } |
1214 | 0 | } |
1215 | 0 | VP8SetIntraUVMode(it, rd->mode_uv); |
1216 | 0 | AddScore(rd, &rd_best); |
1217 | 0 | if (dst != dst0) { // copy 16x8 block if needed |
1218 | 0 | VP8Copy16x8(dst, dst0); |
1219 | 0 | } |
1220 | 0 | if (it->top_derr != NULL) { // store diffusion errors for next block |
1221 | 0 | StoreDiffusionErrors(it, rd); |
1222 | 0 | } |
1223 | 0 | } |
1224 | | |
1225 | | //------------------------------------------------------------------------------ |
1226 | | // Final reconstruction and quantization. |
1227 | | |
1228 | | static void SimpleQuantize(VP8EncIterator* WEBP_RESTRICT const it, |
1229 | 0 | VP8ModeScore* WEBP_RESTRICT const rd) { |
1230 | 0 | const VP8Encoder* const enc = it->enc; |
1231 | 0 | const int is_i16 = (it->mb->type == 1); |
1232 | 0 | int nz = 0; |
1233 | |
|
1234 | 0 | if (is_i16) { |
1235 | 0 | nz = ReconstructIntra16(it, rd, it->yuv_out + Y_OFF_ENC, it->preds[0]); |
1236 | 0 | } else { |
1237 | 0 | VP8IteratorStartI4(it); |
1238 | 0 | do { |
1239 | 0 | const int mode = |
1240 | 0 | it->preds[(it->i4 & 3) + (it->i4 >> 2) * enc->preds_w]; |
1241 | 0 | const uint8_t* const src = it->yuv_in + Y_OFF_ENC + VP8Scan[it->i4]; |
1242 | 0 | uint8_t* const dst = it->yuv_out + Y_OFF_ENC + VP8Scan[it->i4]; |
1243 | 0 | MakeIntra4Preds(it); |
1244 | 0 | nz |= ReconstructIntra4(it, rd->y_ac_levels[it->i4], |
1245 | 0 | src, dst, mode) << it->i4; |
1246 | 0 | } while (VP8IteratorRotateI4(it, it->yuv_out + Y_OFF_ENC)); |
1247 | 0 | } |
1248 | |
|
1249 | 0 | nz |= ReconstructUV(it, rd, it->yuv_out + U_OFF_ENC, it->mb->uv_mode); |
1250 | 0 | rd->nz = nz; |
1251 | 0 | } |
1252 | | |
1253 | | // Refine intra16/intra4 sub-modes based on distortion only (not rate). |
1254 | | static void RefineUsingDistortion(VP8EncIterator* WEBP_RESTRICT const it, |
1255 | | int try_both_modes, int refine_uv_mode, |
1256 | 0 | VP8ModeScore* WEBP_RESTRICT const rd) { |
1257 | 0 | score_t best_score = MAX_COST; |
1258 | 0 | int nz = 0; |
1259 | 0 | int mode; |
1260 | 0 | int is_i16 = try_both_modes || (it->mb->type == 1); |
1261 | |
|
1262 | 0 | const VP8SegmentInfo* const dqm = &it->enc->dqm[it->mb->segment]; |
1263 | | // Some empiric constants, of approximate order of magnitude. |
1264 | 0 | const int lambda_d_i16 = 106; |
1265 | 0 | const int lambda_d_i4 = 11; |
1266 | 0 | const int lambda_d_uv = 120; |
1267 | 0 | score_t score_i4 = dqm->i4_penalty; |
1268 | 0 | score_t i4_bit_sum = 0; |
1269 | 0 | const score_t bit_limit = try_both_modes ? it->enc->mb_header_limit |
1270 | 0 | : MAX_COST; // no early-out allowed |
1271 | |
|
1272 | 0 | if (is_i16) { // First, evaluate Intra16 distortion |
1273 | 0 | int best_mode = -1; |
1274 | 0 | const uint8_t* const src = it->yuv_in + Y_OFF_ENC; |
1275 | 0 | for (mode = 0; mode < NUM_PRED_MODES; ++mode) { |
1276 | 0 | const uint8_t* const ref = it->yuv_p + VP8I16ModeOffsets[mode]; |
1277 | 0 | const score_t score = (score_t)VP8SSE16x16(src, ref) * RD_DISTO_MULT |
1278 | 0 | + VP8FixedCostsI16[mode] * lambda_d_i16; |
1279 | 0 | if (mode > 0 && VP8FixedCostsI16[mode] > bit_limit) { |
1280 | 0 | continue; |
1281 | 0 | } |
1282 | | |
1283 | 0 | if (score < best_score) { |
1284 | 0 | best_mode = mode; |
1285 | 0 | best_score = score; |
1286 | 0 | } |
1287 | 0 | } |
1288 | 0 | if (it->x == 0 || it->y == 0) { |
1289 | | // avoid starting a checkerboard resonance from the border. See bug #432. |
1290 | 0 | if (IsFlatSource16(src)) { |
1291 | 0 | best_mode = (it->x == 0) ? 0 : 2; |
1292 | 0 | try_both_modes = 0; // stick to i16 |
1293 | 0 | } |
1294 | 0 | } |
1295 | 0 | VP8SetIntra16Mode(it, best_mode); |
1296 | | // we'll reconstruct later, if i16 mode actually gets selected |
1297 | 0 | } |
1298 | | |
1299 | | // Next, evaluate Intra4 |
1300 | 0 | if (try_both_modes || !is_i16) { |
1301 | | // We don't evaluate the rate here, but just account for it through a |
1302 | | // constant penalty (i4 mode usually needs more bits compared to i16). |
1303 | 0 | is_i16 = 0; |
1304 | 0 | VP8IteratorStartI4(it); |
1305 | 0 | do { |
1306 | 0 | int best_i4_mode = -1; |
1307 | 0 | score_t best_i4_score = MAX_COST; |
1308 | 0 | const uint8_t* const src = it->yuv_in + Y_OFF_ENC + VP8Scan[it->i4]; |
1309 | 0 | const uint16_t* const mode_costs = GetCostModeI4(it, rd->modes_i4); |
1310 | |
|
1311 | 0 | MakeIntra4Preds(it); |
1312 | 0 | for (mode = 0; mode < NUM_BMODES; ++mode) { |
1313 | 0 | const uint8_t* const ref = it->yuv_p + VP8I4ModeOffsets[mode]; |
1314 | 0 | const score_t score = VP8SSE4x4(src, ref) * RD_DISTO_MULT |
1315 | 0 | + mode_costs[mode] * lambda_d_i4; |
1316 | 0 | if (score < best_i4_score) { |
1317 | 0 | best_i4_mode = mode; |
1318 | 0 | best_i4_score = score; |
1319 | 0 | } |
1320 | 0 | } |
1321 | 0 | i4_bit_sum += mode_costs[best_i4_mode]; |
1322 | 0 | rd->modes_i4[it->i4] = best_i4_mode; |
1323 | 0 | score_i4 += best_i4_score; |
1324 | 0 | if (score_i4 >= best_score || i4_bit_sum > bit_limit) { |
1325 | | // Intra4 won't be better than Intra16. Bail out and pick Intra16. |
1326 | 0 | is_i16 = 1; |
1327 | 0 | break; |
1328 | 0 | } else { // reconstruct partial block inside yuv_out2 buffer |
1329 | 0 | uint8_t* const tmp_dst = it->yuv_out2 + Y_OFF_ENC + VP8Scan[it->i4]; |
1330 | 0 | nz |= ReconstructIntra4(it, rd->y_ac_levels[it->i4], |
1331 | 0 | src, tmp_dst, best_i4_mode) << it->i4; |
1332 | 0 | } |
1333 | 0 | } while (VP8IteratorRotateI4(it, it->yuv_out2 + Y_OFF_ENC)); |
1334 | 0 | } |
1335 | | |
1336 | | // Final reconstruction, depending on which mode is selected. |
1337 | 0 | if (!is_i16) { |
1338 | 0 | VP8SetIntra4Mode(it, rd->modes_i4); |
1339 | 0 | SwapOut(it); |
1340 | 0 | best_score = score_i4; |
1341 | 0 | } else { |
1342 | 0 | nz = ReconstructIntra16(it, rd, it->yuv_out + Y_OFF_ENC, it->preds[0]); |
1343 | 0 | } |
1344 | | |
1345 | | // ... and UV! |
1346 | 0 | if (refine_uv_mode) { |
1347 | 0 | int best_mode = -1; |
1348 | 0 | score_t best_uv_score = MAX_COST; |
1349 | 0 | const uint8_t* const src = it->yuv_in + U_OFF_ENC; |
1350 | 0 | for (mode = 0; mode < NUM_PRED_MODES; ++mode) { |
1351 | 0 | const uint8_t* const ref = it->yuv_p + VP8UVModeOffsets[mode]; |
1352 | 0 | const score_t score = VP8SSE16x8(src, ref) * RD_DISTO_MULT |
1353 | 0 | + VP8FixedCostsUV[mode] * lambda_d_uv; |
1354 | 0 | if (score < best_uv_score) { |
1355 | 0 | best_mode = mode; |
1356 | 0 | best_uv_score = score; |
1357 | 0 | } |
1358 | 0 | } |
1359 | 0 | VP8SetIntraUVMode(it, best_mode); |
1360 | 0 | } |
1361 | 0 | nz |= ReconstructUV(it, rd, it->yuv_out + U_OFF_ENC, it->mb->uv_mode); |
1362 | |
|
1363 | 0 | rd->nz = nz; |
1364 | 0 | rd->score = best_score; |
1365 | 0 | } |
1366 | | |
1367 | | //------------------------------------------------------------------------------ |
1368 | | // Entry point |
1369 | | |
1370 | | int VP8Decimate(VP8EncIterator* WEBP_RESTRICT const it, |
1371 | | VP8ModeScore* WEBP_RESTRICT const rd, |
1372 | 0 | VP8RDLevel rd_opt) { |
1373 | 0 | int is_skipped; |
1374 | 0 | const int method = it->enc->method; |
1375 | |
|
1376 | 0 | InitScore(rd); |
1377 | | |
1378 | | // We can perform predictions for Luma16x16 and Chroma8x8 already. |
1379 | | // Luma4x4 predictions needs to be done as-we-go. |
1380 | 0 | VP8MakeLuma16Preds(it); |
1381 | 0 | VP8MakeChroma8Preds(it); |
1382 | |
|
1383 | 0 | if (rd_opt > RD_OPT_NONE) { |
1384 | 0 | it->do_trellis = (rd_opt >= RD_OPT_TRELLIS_ALL); |
1385 | 0 | PickBestIntra16(it, rd); |
1386 | 0 | if (method >= 2) { |
1387 | 0 | PickBestIntra4(it, rd); |
1388 | 0 | } |
1389 | 0 | PickBestUV(it, rd); |
1390 | 0 | if (rd_opt == RD_OPT_TRELLIS) { // finish off with trellis-optim now |
1391 | 0 | it->do_trellis = 1; |
1392 | 0 | SimpleQuantize(it, rd); |
1393 | 0 | } |
1394 | 0 | } else { |
1395 | | // At this point we have heuristically decided intra16 / intra4. |
1396 | | // For method >= 2, pick the best intra4/intra16 based on SSE (~tad slower). |
1397 | | // For method <= 1, we don't re-examine the decision but just go ahead with |
1398 | | // quantization/reconstruction. |
1399 | 0 | RefineUsingDistortion(it, (method >= 2), (method >= 1), rd); |
1400 | 0 | } |
1401 | 0 | is_skipped = (rd->nz == 0); |
1402 | 0 | VP8SetSkip(it, is_skipped); |
1403 | 0 | return is_skipped; |
1404 | 0 | } |